Storing a video program for later watching has been a desirable goal of many systems. In the original days of video, the video stream could only be watched if the watcher were available at precisely the time the video stream was being broadcast. Different kinds of media for storing video such as video discs and the like, were eventually invented so that a user could watch video on demand. Videocassette recorders, or VCRs then allowed video to be recorded for time shifting purposes. Even though these devices allowed watchers to fast-forward over the commercials, the U.S. Supreme Court nonetheless found that recording this kind of information for later viewing was in fact “fair use” of the broadcaster's copyright.
Technology has made more sophisticated devices available. For example, the personal video recorder or digital video recorder, also known as the home theater PC or HTPC, allows video programming to be copied from a broadcast medium, and played back later. The programs are recorded digitally, and can be randomly selected during playback.
With the advent of digital television, the broadcasters and other copyright holders have become increasingly concerned that the personal video recorder can obtain a raw digital version of the transmitted program and use that raw digital information to circumvent the copyright. Different suggestions have emerged for dealing with the copyright issue, but most of these end up putting significant restrictions on the eventual viewing.